The problem that this design solves is when winds outside of a building blow across the exhaust ventilation opening, like a bathroom fan, cooking exhaust fan or clothes dryer. The Ventura affect the wind outside of a building generates in the exhaust vent piping, lifts the light, flat trap door that most of the above mentioned devices now employ. This should lead to improved energy efficiency with buildings using devices that utilize this design. This should keep heated air inside of the building during the winter months and vice versa, cooler air inside during the summer months when the buildings are using air conditioning. On heating devices like fireplaces, water heaters and furnaces, this design would be utilized by closing the exhaust ventilation pipe to inhibit a heat induced draft in the exhaust piping and hold more of the heat in the device thus making them more energy efficiency too.